Mitchells & Butlers shares enjoyed their biggest gain in more than a month following a move by the pub group’s largest shareholder to increase his stake.

Joe Lewis, the Bahamas-based billionaire who became M&B’s largest shareholder last year after buying Robert Tchenguiz’s stake at a fire-sale price, increased his holding in the company through his Piedmont investment vehicle from 21.8 per cent to 22.3 per cent.